GB2090815A

GB2090815A - Removing batches of sheets from a stack

Info

Publication number: GB2090815A
Application number: GB8040245A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-12-16
Filing date: 1980-12-16
Publication date: 1982-07-21
Also published as: GB2090815B

Abstract

Batches of sheets (12) are separated from a stack (4) which has already been subdivided by the insertion of tabs into one edge by a pivotally mounted suction device 1 moved into contact with a tab to lift the tab and adjacent edge of the batch (12) of sheets above it. A reciprocable batch gripper (2, 3) is then moved in to grip the raised edge of the batch and, after release of the suction device, initially to pull the batch to the right and then to push it laterally in the opposite direction. A batch separator (6) moves, following initial displacement of the batch (12) to the right, into the space left by the displacement of the edge of the batch (12) opposite to that gripped by the gripper (2, 3). A take-off device (8, 9) is then operative on said opposite edge of the batch (12) for onward feeding. <IMAGE>

Description

SPECIFICATION Sheet-feeder This invention relates to the feeding of sheets from a stack and is particularly, though not exclusively, concerned with the collation of sheets of paper or like material.

In the formation of books, e.g. cheque books, which have a number of identical pages it is still necessary, with standard collating machines, to provide as many different stacks of sheets as there are pages required in the book to be formed. If however, a stack of identical sheets is divided, by the insertion of tabs, during its formation, into batches each containing the number of sheets required to form one section of the book to be produced and each batch is fed from the stack in one operation, then the number of stacks or sheets required in the collating machine will be considerably reduced.

It is the principal object of the invention, therefore, to provide means for automatically feeding batches of sheets from a stack which has already been subdivided by the insertion of tabs at predetermined intervals during its formation, and to this end, according to the invention, there is provided first means operable on the uppermost tab to initially raise said tab and the associated edge of the batch of sheets above it, second means operable on said raised edge of the batch, after release of said first means, to first pull the batch partly across the stack in one direction and then push the batch across the stack in the opposite direction, and third means operable to engage the top of the stack and to serve, during the pushing action of said second means to separate the opposite edge of the batch from the stack and fourth means operable to grip said opposite edge and, following release of said second means, to remove the batch from the stack for forward feeding.

One embodiment of the invention will be described by way of example, with reference to the accompanying drawings in which Figs.

1 to 5 illustrate, diagrammatically, successive steps in the operation of the apparatus.

In this embodiment a pivotally mounted device 1 is adapted to be connected to a source of vacuum (not shown) and a pair of jaws 2, 3 are individually reciprocable towards and away from a stack 4 of paper sheets with the jaw 3 pivotable about an axis 5 towards and away from the jaw 2. A finger 6 is reciprocable in a vertical direction along one edge 7 of the stack 4 remote from the jaws 2, 3 and is also reciprocable in a horizontal direction towards and away from the stack, and a clamping device 8 (Fig. 5) is mounted on a conveyor 9 on the same side of the stack as the finger 6.

In operation, the device 1 is moved downwardly about its pivotal axis into contact with the uppermost tab 10 projecting from the associated edge 11 of the stack 4 and is connected to the source of vacuum to apply suction to the tab. The device 1 is then pivoted in an upward direction, as shown in Fig. 2, lifting the tab 10 and the batch 1 2 of paper above it until a small gap 1 3 is created between the topmost batch 1 2 and the rest of the stack 4. The jaw 2 is then moved into the gap 1 3 allowing the device 1 to be disconnected from the source of vacuum and pivoted out of the path of the jaw 3 which, as shown in Fig. 3, is then moved towards the stack 4 and is pivoted about the axis 5 into engagement with the top of the batch 12.The top batch 12 is now gripped by the jaws 2, 3, which, as shown in Fig. 4, are then moved horizontally in the direction of the arrow 14 away from the stack 4 until the opposite edge 1 5 of the batch is spaced sufficiently from the adjacent edge 7 of the stack to permit the finger 6 to move inwardly until it rests on the top of the stack. The movement of the jaws 2, 3 is then reversed to push the batch 1 2 in the opposite direction indicated by the arrow 16, whereupon the edge 1 5 thereof passes over the finger 6, which, as shown in Fig. 5, separates it from the top of the stack 4, and into the clamp 8. When the clamp 8 closes and the jaws 2, 3 open, the clamp moved by the conveyor 9, feeds the batch 1 2 to its final destination.

When a longer tab 1 9 (Fig. 1) has been inserted in the stack 4 to denote a fault or other peculiarity in the batch 20 a device 21 of any suitable kind, positioned beyond the outer edges of the normal-sized tabs 10, is operable to detect the presence of the tab 1 9 and any other tab of greater than normal length and transmit a suitable signal which either stops the machine or warns the operator of the presence of an abnormal batch.

When handling difficult paper it may be advantageous to provide a second finger 22 (Fig. 2) on the same side of the stack 4 as the jaws 2, 3, said finger being designed to move into the gap 1 3 created by the suction device 1, alongside the jaw 2 and hold down the top sheet of the main stack while the upper batch 1 2 is being moved to the right by the jaws 2, 3, as seen in Fig. 4 of the drawing.

The apparatus is designed for use with a stack 4 which is raised after each batch 1 2 has been removed therefrom and the finger 6, in its normal poistion, can be used as a detector to ensure that the stack has been raised sufficiently for the suction device 1 to locate the next tab 10.

If the vertical distance between successive tabs 10 should vary for any reason, the suction device 1 is preferably employed to stop the mechanism for raising the stack 4 when the next tab comes into contact with it.

For use with stacks in which the tabs are arranged in staggered vertical planes the suc tion device 1 is preferably programmed to move horizontally along the side of the stack into alignment with successive tabs.

Although the invention has been described with reference to the collation of paper sheets it will be understood that it also has many other applications among which are the feeding of sheets of plywood, metal and other materials.

Claims

1. A method of automatically separating and feeding batches of sheets from a stack which has already been subdivided by the insertion of tabs into one edge of the stack at predetermined intervals during its formation, said method comprising the steps of raising the uppermost tab and with it the associated edge of the batch of sheets above it, operating on said raised edge of the batch to displace the batch laterally relative to the stack, inserting a separator into the space left at the opposite edge of the stack by the displacement of the batch, operating on said raised edge of the batch to displace the batch laterally in the opposite direction over said separator to separate the opposite edge of the batch from the stack, releasing said initially raised edge and operating on said opposite edge of the batch to remove the latter from the stack for onward feeding.

2. Apparatus for carrying out the method claimed in Claim 1, comprising a pivotally mounted suction device for location on one side of the stack and operable on the uppermost tab to initially raise the tab and the associated edge of the batch of sheets above it, a reciprocable batch displacement device for location on the same side of the stack as said suction device and provided with jaws for gripping the edge of a batch of sheets initially raised by said suction device, a batch separator for location on the opposite side of the stack from said suction and displacement devices and movable, after initial movement of said displacement device in one direction, into the space left by lateral displacement of the batch, and a take-off device for location on the same side of the stack as said separator and operable, following movement of said displacement device in the opposite direction, to receive the opposite edge of the displaced batch of sheets and remove it from the stack for onward feeding.

3. Apparatus according to Claim 2, wherein said suction device is pivotable about a substantially horizontal axis into engagement with the upper surface of a tab and is automatically connectible to a source of vacuum.

4. Apparatus according to Claim 2 or 3, wherein said displacement device is initially movable in a substantially horizontal direction before closure of its jaws to place one jaw thereof in a position to maintain the edge of the batch in its raised position when the suction device is disconnected from the vacuum source.

5. Apparatus according to Claim 4, wherein following closure of its jaws, said displacement device is movable in a direction opposite to its initial direction of movement to effect the first displacement of the batch.

6. Apparatus according to any one of Claims 2 to 5, wherein said take-off device is a clamp, the jaws of which are closed prior to the opening of the jaws on said displacement device.

7. Apparatus according to any one of Claims 2 to 6, wherein said take-off device is one of a plurality of similar devices mounted at intervals on an endless conveyor for feeding successive batches of sheets to their final destination.

8. Apparatus according to any one of Claims 2 to 7, provided with a device located on the same side of a stack as said suction device, for detecting the presence of tabs of greater than normal length inserted in the stack to denote a batch possessing a fault or other peculiarity.

9. Apparatus according to Claim 8, wherein said detector device is adapted to transmit a control or warning signal on detecting an oversize tab.

10. Apparatus according to any one of Claims 2 to 9, including a device for location on the same side of the stack as said suction and displacement devices and movable into a position to hold down the top sheet of the remainder of the stack during separation and removal of each batch.

11. Apparatus according to any one of Claims 2 to 10, wherein means are provided for indexing the pivotal mounting for said suction device in a direction at right angles to the direction of reciprocable movement of said displacement device to gradually move said suction device along one side of the stack.

12. Apparatus according to any one of Claims 2 to 11, wherein said batch separator is a finger which is reciprocable in substantially vertical and horizontal directions.

13. Apparatus according to Claim 12, for use with a stack which is raised following removal of each batch of sheets therefrom, wherein said finger is operable to detect the level of the top of the stack and prevent the start of a new cycle of operation until the stack has been raised sufficiently for the suction device to locate the next tab.

14. Apparatus according to Claim 13, wherein means are provided for interrupting the operation of the stack-raising mechanism whenever the suction device comes into contact with a tab.

1 5. A method of automatically separating and feeding batches of sheets from a stack, substantially as hereinbefore described with reference to the accompanying drawings.

1 6. Apparatus for automatically separating and feeding batches of sheets from a stack, substantially as hereinbefore described with reference to the accompanying drawings.